This is a good game to practice various forms of the past tense. I've used it with great success with middle school kids during private tutoring (1on1) sessions.

First teach them a verb tense i.e. past simple, then get them to do some exercises so they are comfortable with it. Next you have to build up the story... Tell them they are a detective (explain it if they are unfamiliar with the vocab) and pretend to be a distressed lady who has had her purse stolen. It helps a lot if you can think up funny names for your characters (I call the lady "Mrs. Pusan Kimchi"). Have the lady describe when and where it was stolen (i.e. From Georgia and Burrard at 10pm on Thurdsday). Then inform the detective that there are 3 suspects (once again introduce vocab). Have other students act out the suspects or do it yourself (again giving clever names) and create a "bio" for each suspect that outlines what he/she does and what they were doing the night of the robbery. Now the detective has to use the correct past verb tense to question the suspects and determine which one most likely stole the purse. If they do not use the correct verb tense just say something like "I'm sorry, I may be a criminal but since I love english so much, I can only answer questions if they use proper grammer."Most students find this game fun especially if you include props (i.e a gun or a badge or something), use funny names and situations, and get them (and you) to really act out the characters.